Various methods of manufacturing contact lenses are known, including spin casting, lathing (for example, by diamond turning) and cast molding (for example, using injection molded mold halves). Manufacture of soft contact lenses, including conventional hydrogel and silicone hydrogel contact lenses, presents particular difficulties, as contact lenses are delicate. Surfaces and edges of a contact lens, including surfaces providing vision correction, as well as surfaces and edges used to cast mold surfaces of a contact lens, must be manufactured and maintained to optical precision and all surfaces and edges must be manufactured within tight tolerances to provide a desired level of vision correction and/or provide a desired cosmetic appearance to the eye, and to avoid potential issues with discomfort or even damage to the eye of the wearer. Using high speed manufacturing lines, contact lenses can be manufactured in very large numbers, for example, tens of thousands each day. Increases in the rate of manufacture of contact lenses can be expected to bring down the cost of each lens. It is important, however, that increased rates of manufacture do not compromise the quality of the lenses produced.